1. Field of the Invention
The present invention relates generally to tools for opening and closing (i.e., exercising) valves. In another aspect, the invention concerns power valve operators for exercising valves having valve nuts that turn on a generally upright axis of rotation.
2. Description of the Prior Art
Many large valves are exercised by rotating a valve nut coupled to the body of the valve. Examples of valves that operate in this manner include valves employed in fire hydrants, underground water lines, water treatment plants, and petroleum product lines. Typically, such valves require a high magnitude of torque to rotate the valve nut. Further, such valves require relatively slow and constant turning of the valve nut in order to prevent damaging pressure surges upstream and downstream of the valve.
In the past, a variety of configurations of the manual and power valve operating devices have been employed to exercise valves via rotation of the valve nut. The prior art manual valve operators generally comprise a key for coupling the device to the valve nut and one or more elongated handles for increasing the amount of torque that can be manually applied to the valve nut. Although prior art manual valve operators are relatively inexpensive and portable, such manual devices have a number of drawbacks. For example, manually turning of the valve nut can be a slow and physically exhausting task, especially when the exercised valves require high torque and many rotations of the valve nut. When the valve is being closed in order to terminate flow to a damaged and leaking line, slow manual turning of the valve nut can allow excessive amounts of fluids to escape the leaking line during manual exercising of the valve, thereby risking further damage to the surroundings due to excessive fluid leakage. Physical exhaustion of the workers operating the manual valve operator can increase the risk of injury to the workers and/or increase the risk of worker error during performance of the desired task. When the valve being manually exercised is positioned in a dangerous location (e.g., an underground water valve accessible through a port in a city street), the slow valve-turning required by manual valve operators can increase the exposure of the workers to such dangerous conditions. In addition, the light weight of most manual valve operators creates a need for the workers to continually exert a downward holding force on the key while turning the valve nut in order to prevent disengagement of the key from the valve nut, which can become stripped (i.e., rounded-off) when the valve operator becomes disengaged during turning.
Prior art power (i.e., automatic) valve operators are typically mounted on vehicles. Such vehicle-mounted power valve operators can deliver high magnitudes of torque in a relatively rapid and continuous manner while exerting sufficient downward force on the key to maintain engagement of the key and the valve nut. However, vehicle-mounted power valve operators have a number of drawbacks. For example, such vehicle-mounted power valve operators are expensive to purchase and mount on the vehicle. Further, it can be very difficult to properly align the key of a vehicle-mounted power valve operator with the valve nut to be turned, especially when faced with adverse surface conditions such as, for example, snow, mud, and/or ice.
The prior art also includes portable (i.e., non vehicle-mounted) power valve operators. Such portable power valve operators typically are fairly lightweight and do not produce a sufficient amount of torque to exercise larger valves. Further, the light weight of these portable devices can cause the key to become disengaged from the valve nut unless a continuous manual downward force is exerted on the key by the workers operating the device.
It is, therefore, an object of the present invention to provide a portable valve operator that minimizes physical fatigue of workers operating the device.
A further object of the invention is to provide a power valve operator that can exercise valves more rapidly than manual means.
A still further object of the invention is to provide a portable valve operator having sufficient weight to prevent disengagement of the key from the valve nut without requiring application of a manual external downward force to the valve operator.
Another object of the invention is to provide a valve operator producing a relatively smooth and slow rotation that prevents pressure surges upstream and downstream of the valve when the valve is exercised.
Still another object of the invention is to provide a portable power valve operator operable to generate a sufficient amount of torque to operate large valves.
Yet another object of the invention is to provide a power valve operator that facilitates easy manual alignment of the key with the valve nut.
Yet still another object of the invention is to provide an improved method of exercising a valve using a power valve operator.
It should be understood that the above-listed objects are only exemplary, and not all the objects listed above need be accomplished by the invention described and claimed herein.
Accordingly, in one embodiment of the present invention, there is provided a tool for rotating a valve nut. The tool comprises an elongated key, a powering device, and a weighted handle. The key has a first end adapted to matingly engage the valve nut. The powering device includes a housing and a rotation element. The rotation element is drivingly coupled to the second end of the key. The powering device is operable to cause rotation of the rotation element relative to the housing. The handle is rigidly coupled to the housing and extends generally outwardly from the axis of elongation of the key. The handle has a center of gravity that is at least substantially centered on the axis of elongation of the key.
In another embodiment of the present invention, there is provided a valve operator for rotating a valve nut of a valve to thereby exercise the valve. The valve operator comprises an elongated key and a powering assembly. The elongated key presents a normally lower end for releasably and matingly engaging the valve nut. The powering assembly presents a rotation element adapted to releasably and matingly engage a normally upper end of the key. The powering assembly includes a powering device and a handle. The powering device is operable to rotate the rotation element relative to the handle. The powering assembly has a center of gravity that is at least substantially centered on the axis of rotation of the rotation element.
In still another embodiment of the present invention, there is provided a method of operating a valve having a valve nut that can be rotated on a generally upright axis of rotation to thereby exercise the valve. The method comprises the steps of: (a) coupling a normally lower end of an elongated key to the valve nut; (b) while the key is coupled to the valve nut, coupling a powering assembly to a normally upper end of the key, said powering assembly including a powering device and a handle; and (c) actuating the powering device to thereby cause the key and the valve nut to rotate relative to the handle.
In yet another embodiment of the present invention, there is provided a method of operating a valve having a valve nut that can be rotated on a generally upright axis of rotation to thereby exercise the valve. The method comprises the steps of: (a) coupling a key of a power valve operator to the valve nut; (b) substantially aligning the center of gravity of the power valve operator with the axis of rotation of the valve nut; and (c) simultaneously with step (b), using the power valve operator to rotate the valve nut.